Rapid development of anoxic niches in supraglacial ecosystems

• Main Authors: Poniecka, Ewa A., Bagshaw, Elizabeth A., Tranter, Martyn, Sass, Henrik, Williamson, Christopher J., Anesio, Alexandre M., Team, Black and Bloom
• Format: Text
• Language: unknown
• Published: Taylor & Francis 2021
• Subjects: Biochemistry; Medicine; 59999 Environmental Sciences not elsewhere classified; FOS Earth and related environmental sciences; Ecology; FOS Biological sciences; 69999 Biological Sciences not elsewhere classified; Developmental Biology; Inorganic Chemistry; FOS Chemical sciences; Greenland; Ice Sheet
• Online Access: https://dx.doi.org/10.6084/m9.figshare.6114644; https://tandf.figshare.com/articles/journal_contribution/Rapid_development_of_anoxic_niches_in_supraglacial_ecosystems/6114644

Microorganisms play a significant role in changing the physical properties of the surface of the Greenland Ice Sheet. Cryoconite holes are a hotspot for this microbial activity, yet little is known about the REDOX conditions that develop within them. In this study, we used oxygen microelectrodes and microoptodes to measure for anoxic conditions at the microscale, for the first time revealing a potential niche for anaerobic microorganisms and anaerobic processes. The development of an anoxic zone 2 mm deep within a 6 mm-thick layer of cryoconite sediment was observed within an hour of disturbance, showing rapid acclimation to changing physical conditions. Long-term (half year) incubations of cryoconite material showed a peak of oxygen production and consumption after forty days and reached a low-activity, steady state by day 116, with a persisting anoxic zone beginning between 2 mm and 4 mm deep. Anaerobic microorganisms, which have received little attention to date, should therefore be considered an important component of the cryoconite ecosystem. We discuss the possible dynamics of oxygen concentrations in the supraglacial system and infer that anoxic zones are an important factor in the development of cryoconite sediment communities.